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Service
Manual
SM 648
CMP 40/45/50S
Copyrighted Material
Intended for CLARK dealers only
Do not sell or distribute

Copyrighted Material
Intended for CLARK dealers only
Do not sell or distribute
Arrangement and Use of this Manual
Clark arranges parts and service procedures by standard-
ized Groups. In this manual, Groups are similar to “chap-
ters.” Groups are listed in the table of contents on the next
page.
You can quickly locate a specific point in the manual by
using the headers and footers that appear on the pages. The
following illustration points out these areas.
Each Group begins with a table of contents that shows the
Sections contained within the Group. Lengthy Sections
also begin with a table of contents showing the topics
contained within the Section.
Group ID
Each Group and Section has an identifying name and
number, or “ID.”
Each page also has a unique ID. The page ID consists of
three numbers separated by hyphens. The three numbers
represent the Group number, the Section number, and the
page number. For example, “00-1-2” on the lower comer
of the page indicates Group 00, Section 1, Page 2.
Page ID
Section ID
This manual is intended for the use of trained service
personnel. Please read Group SA, “Safe Maintenance,”
and the Operator’s Manual before working on or operat-
ing the truck.
0 Copyright Clark Material Handling Company 1999
SM 648, July ‘99
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CONTENTS
Contents
Contents are listed by Group number and name followed by Section number and name:
SA
PS
00
01
06
14
16
23
SAFE MAINTENANCE
1. Safety
2. Lifting, Jacking, and Bloc
3. Towing
PERIODIC SERVICE
1. Maintenance Schedules
2. Planned Maintenance
3. PM Inspection Form
ENGINE
:king
25126 STEER SYSTEM
1. Specifications and Description
2. Troubleshooting
3. Steering System Removals 81 Installations
4. Steering System Pressure Check
5. Steering Unit Overhaul
6. Priority Valve Overhaul
7. Steer Cylinder Overhaul
29/30 HYDRAULIC SYSTEM
1. Perkins Diesel Engine Service Manual
COOLING SYSTEM
1. Specifications and Description
2. Troubleshooting
TRANSAXLE
1. Specifications and Description
2. Fluid Level Check and Fill
3. Checks and Troubleshooting
3. Transaxle Overhaul
ELECTRICAL
1. Circuit Diagram
2. Instrument Pod
WHEELS AND TIRES
1. Specifications and Description
2. Cushion Wheels and Tires
3. Pneumatic Wheels and Tires
34
38
40
BRAKE SYSTEM
1. Specifications
2. Service/Inching Brake
3. Parking Brake
1. Specifications and Description
2. Troubleshooting
3. Hydraulic Pump Overhaual
4. Control Valve Overhaul
UPRIGHTS
1. Specifications and Description
2. Upright Checks and Adjustments
3. Lift Chain Service
4. Removals and Replacements
5. Lift and Tilt Cylinder Overhaul
COUNTERWEIGHT
1. Specifications
2. Inspection
3. Removal and Replacement
SPECIFICATIONS
1. Specifications
SM 648, July ‘99 Contents-iii
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GROUP SA
GROUP SA
SAFE MAINTENANCE
Safety ............................................................................... Section 1
Lifting, Jacking, and Blocking the Truck.. ................... Section 2
Towing .............................................................................. Section 2
SM 648, July ‘99 Safe Maintenance
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CMRK
Group SA, Safe Maintenance
Section 1. Safety
Safety Signs and Messages Safe Maintenance Practices
Safety signs and messages in this manual and on the lift
truck provide instructions and identify specific areas where
potential hazards exist and special precautions should be
taken. Be sure you know and understand the meaning of
these instructions, signs, and messages. Damage to the
truck, death, or serious injury to you or other persons may
result if these messages are not followed.
NOTE
This message is used when special informa-
tion, instructions or identification is re-
quired relating to procedures, equipment,
tools, pressures, capacities, and other spe-
cial data.
The following instructions have been prepared from cur-
rent industry and government safety standards applicable
to industrial truck operation and maintenance. These rec-
ommended procedures specify conditions, methods, and
accepted practices that aid in the safe maintenance of in-
dustrial trucks. They are listed here for the reference and
safety of all workers during maintenance operations. Care-
fully read and understand these instructions and the spe-
cific maintenance procedures before attempting to do any
repair work.
When in doubt of any maintenance procedure, please con-
tact your local Clark dealer.
1.
IMPORTANT
Powered industrial trucks can become hazardous if
maintenance is neglected. Therefore, suitable mainte-
nance facilities, trained personnel, and procedures
must be provided.
This message is used when special precau-
tions should be taken to ensure a correct
action or to avoid damage to, or malfunc-
tion of, the truck or a component.
2. Maintenance and inspection of all powered industrial
trucks shall be done in conformance with the
manufacturer’s recommendations.
3.
A
CAUTION
This message is used as a reminder of safety
hazards that can result in personal injury
if proper precautions are not taken.
A scheduled planned maintenance, lubrication, and
inspection program shah be followed.
4. Only trained and authorized personnel shah be permit-
ted to maintain, repair, adjust, and inspect industrial
trucks. Work should be performed in accordance with
the manufacturer’s specifications.
A
WARNING
This message is used when a hazard exists
that can result in injury or death if proper
precautions are not taken.
5. Properly ventilate work area, vent exhaust fumes, and
keep shop clean and floor dry.
6.
A
DANGER
This message is used when an extreme haz-
ard exists that can result in injury or death
or serious injury if proper precautions are
not taken.
Avoid fire hazards and have fire protection equipment
present in the work area. Do not use an open flame to
check for level or leakage of fuel, electrolyte, or
coolant. Do not use open pans of fuel or flammable
cleaning fluids for cleaning parts.
7.
The above terms have been adopted by Clark Material
Handling Company. The same terms may be used in differ-
ent context in service literature supplied directly or indi-
rectly by vendors of truck components.
Before starting work on truck:
a. Raise drive wheels off of floor or disconnect
power source and use blocks or other positive
truck positioning devices.
b. Disconnect battery before working on the electri-
cal system.
8. Before working on engine fuel system of gasoline- or
diesel-powered trucks, be sure the fuel shut-off valve
is closed.
SM 648, July ‘99 Safety . SA-1-l
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Group SA, Safe Maintenance
CUIRU
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
Operation of the truck to check performance must be
conducted in an authorized, safe, clear area.
Before starting to drive truck:
a. Be in operating position.
b. Be sure parking brake is engaged.
c. Put direction control in neutral.
d. Start engine.
e. Check functioning of direction and speed con-
trols, steering, brakes, warning devices, and any
load handling attachments.
19.
20.
21.
Modifications and additions that affect capacity and
safe truck operation must not be done without the
manufacturer’s prior written approval. Capacity, op-
eration and maintenance instruction plates, tags, or
decals must be changed accordingly. This is an OSHA
requirement.
Before leaving truck
a. Stop truck.
b. Put directional control in neutral.
c. Apply the parking brake.
d. Stop the engine by turning off the ignition circuit.
e. Put blocks at the wheels if truck is on an incline.
Brakes, steering mechanisms, control mechanisms,
warning devices, lights, governors, guards, safety de-
vices, and frame members must be carefully and regu-
larly inspected and maintained in a safe operating
condition.
Care must be taken to assure that all replacement parts,
including tires, are interchangeable with the original
parts and of a quality at least equal to that provided in
the original equipment. Parts, including tires, are to be
installed per the manufacturer’s procedures. Always
use genuine CLARK or CLARK-approved parts.
Use special care when removing heavy components
from the truck, such as counterweight, seat deck,
upright, etc. Be sure that lifting and handling equip-
ment is of the correct capacity and in good condition.
Also, this removal may upset the stability of the truck.
The frame must always be safely blocked for major
component removal.
NOTE
Special trucks or devices designed and approved for
hazardous area operation must receive special atten-
tion to ensure that maintenance preserves the original,
approved, safe-operating features.
You should also he familiar with additional
operating and maintenance safety instruc-
tions contained in the following publica-
tions:
Fuel systems must be checked for leaks and condition
of parts. Extra special consideration must be given in
the case of a leak in the fuel system. Action must be
taken to prevent the use of the truck until the leak has
been corrected.
ANSI/ASME B56.1- 1988 Operator Control-Industrial Tow
Tractors (Safety Standard For Powered Industrial Trucks).
Published by: Society of Mechanical Engineers, United
Engineering Center, 345 E. 47th Street, New York, NY
10017.
The truck manufacturer’s capacity, operation, and
maintenance instruction plates, tags, or decals must be
maintained in legible condition.
NFPA 505-1982: Fire Safety Standard for Powered Indus-
trial Trucks: Type Designations, Areas of Use, Mainte-
nance and Operation. Available from: National Fire
Protection Assoc., Inc., Batterymarch Park, Quincy, MA
02269.
Batteries, motors, controllers, limit switches, protec-
General Industrial Standards, OSHA 2206: OSHA Safety
tive devices, electrical conductors, and connections
and Health Standards (29 CFB 1910), Subpart N-Materials
must be inspected and maintained in conformance
Handling and Storage, Section 1910.178 Powered Indus-
with good practice. Special attention must be paid to
trial Trucks. For sale by: Superintendent of Documents,
the condition of electrical insulation.
U.S. Government Printing Office, Washington, DC 20402.
To avoid injury to personnel or damage to the equip-
ment, consult the manufacturer’s procedures in replac-
ing contacts on any battery connection.
Industrial trucks must be kept in a clean condition to
minimize fire hazards and help in the detection of loose
or defective parts.
SA-1-2 l Safety SM 648, July ‘99
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CUIRK
Group SA, Safe Maintenance
Section 2.
Lifting, Jacking, and Blocking
Safe Parking ...................................................................................................................................
2
Lifting, Jacking, and Blocking Points ..........................................................................................
2
Raising Drive Wheels Off Floor ...................................................................................................
2
Raising Truck with A Hoist ..........................................................................................................
3
Blocking the Upright in Raised Position ......................................................................................
4
Raising Rear of Truck ...................................................................................................................
4
Raising Entire Truck .....................................................................................................................
5
A
WARNING
Lifting or jacking any large piece of equipment such as your fork truck presents
obvious hazards. It must be done with great care and forethought. Consult the
truck weight tabulations in Group 40, “Specifications” to ensure that your
lifting equipment is of adequate capacity.
SM 648, July ‘99 Lifting, Jacking, and Blocking l SA-2-l
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Group SA, Safe Maintenance
CICIRK
Safe Parking
Raising Drive Wheels Off Floor
Before working on truck:
1.
2.
3.
4.
Park truck on a hard, level, and solid surface, such as
a concrete floor with no gaps or breaks.
Put upright in vertical position and fully lower the
forks or attachment.
This procedure uses the upright as a lever to lift the drive
wheels off the floor and prevent accidents due to inadvert-
ent powering of the drive wheels.
Park truck safely as described in “Safe Parking.” Block
steer wheels.
Put all controls in neutral. Turn key switch OFF and
remove key.
Apply the parking brake and block the wheels.
1.
2.
3.
4.
Be sure upright trunnion bolts are tight. Bolt torques
must be 75-80 N*m (55-59 ft-lb).
Start the engine. Tilt the upright fully back. Adjust
upright height as necessary to put blocking underneath
the lower end of the upright.
Put a solid 100 x 100 mm (4 x 4 in) hardwood block
under the front section of each upright rail. Put a 3-6
mm (. 125-.250 in) steel plate on top of each block.
A
WARNING
Defective equipment can cause accidents.
All tools and lifting equipment must be in
good condition, meet the load capacity re-
quirements and have OSHA labels when
required. Tools with defects can have fail-
ures causing severe injury or death.
Lifting, Blocking, and Jacking Points
Use the following illustration to locate general lifting, block-
ing, and jacking points on the truck. Read the procedures
for raising, blocking, or jacking specific components of the
truck to make sure you understand the correct, safe proce-
dures.
‘%nder Steer v Under Frame L Under Upright
Axle Frame
Mount
A
WARNING
Do not attempt to lift the truck by the over-
head guard or the counterweight. Severe
injury may result and the truck can be
damaged.
5. Tilt upright fully forward. This raises the drive wheels
off the floor. Release the tilt control lever and turn
engine OFF.
SA-2-2 l Lifting, Jacking, and Blocking SM 648, July ‘99
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Group SA, Safe Maintenance
6. Insert blocking under the frame behind the drive
wheels or slip wheel cradles under the drive wheels. If
using blocking, check for safe clearance between drive
wheels and floor and blocks.
NOTE
When forks are raised as in illustration
above, use shop rags, paper, or bright tape
on fork tips to signal the danger of trip-
ping.
7. Check for stable condition of the truck. Be sure that the
blocks are located securely under the truck frame
before operating the drive or working on truck.
8. Lower the drive wheels to the floor and remove the
blocks by reversing the above procedure.
Raising Truck with a Hoist
When suitable equipment is available, the front of the truck
may be raised by means of a hoist, with wheel cradles
placed under the wheels or blocking placed under the frame.
1.
2.
A
CAUTION
When lifting the front of the truck watch
truck for signs of lateral instability. It may
tip sideways. You may have to support or
guide the side of the truck or overhead
guard to prevent tipping.
Parktrucksafelyasdescribedin“SafeParking.”Block
rear steer wheels.
Check trunnion bolts to make sure they are tightened to
correct torque. Bolt torques must be 75-80 N-m (55-59
ft-lb).
3. To raise the front of the truck using the upright, spread
two chains on the outer rail tiebar of the upright.
A
WARNING
Chain and hoist used to lift truck should be
checked to make sure they are of safe lift-
ing capacity. See the truck data plate for
information.
4. Slowly lift truck and lower drive wheels onto the
cradles or place blocking under frame prop points.
5. When maintenance work is completed, lower the truck
to the floor by reversing the lifting procedure. Check to
be sure no tools or equipment are under the truck or
wheels.
SM 648, July ‘99 Lifting, Jacking, and Blocking l SA-2-3
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Group SA, Safe Maintenance
CWRU
Blocking the Upright In Raised Position
This procedure is used to safely provide clearance for
access from the front of truck to components on or near the
drive axle. Illustrations show upright with forks removed
however, fork removal is not necessary
1.
2.
3.
4.
5.
6.
Park truck safely as described in “Safe Parking.”
Put blocks in front of and behind drive wheels.
Put wooden support blocks conveniently near upright
rails beforeraising the upright. Use two 100 x 100 mm
(4 x 4 in) hardwood blocks or equal, of about 300 x 300
mm (12 in) and 600 x 600 mm (24 in) length.
NOTE
For standard uprights, block may need
length cut to suit. For triple stage uprights,
the carriage may be blocked up, as shown.
Start engine and raise the upright carriage.
Hold the taller block against inner rail and lower the
upright until carriage rests on block.
Outer
Rail
:.:.:.:.:
. . . . . . . . .
:m
:.:.:.:.:
.:.:.:.:.
w
w
:w
. . . . . . . . . Tall
3 :.:.:.: :::; z
. . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . .
Block
. . . . . . :.:....
Hold the shorter block against the outer rail and lower
the upright until inner rail rests on the block.
Outer
Rail
d IIII~
, * Carriage
7. Reverse the procedure to remove blocking.
Raising Rear of Truck
The truck may be raised at the rear by jacking and blocking
under the center of the frame member at either the front or
rear steer axle mounting. or under the center section of the
steer axle.
Refer to truck data plate for truck weights.
1.
A
WARNING
An incorrectly installed counterweight can
move or fall unexpectedly. Never lift or
block a truck using the counterweight. Fail-
ure to follow procedures outlined in this
manual can result in injury or death.
Park truck safely as described in “Safe Parking.” Put
blocks at front and rear of drive wheels.
SA-2-4 . Lifting, Jacking, and Blocking SM 648, July ‘99
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Intended for CLARK dealers only
Do not sell or distribute
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This workshop service repair manual is an essential resource for maintaining and repairing the Clark CMP 40, CMP 45, and CMP 50S forklift models. It is designed to provide comprehensive guidance for both professional mechanics and DIY enthusiasts.
- The manual covers a wide range of topics including safe maintenance, periodic service, engine, cooling system, transaxle, electrical, wheels and tires, brakes, steering system, hydraulic system, upright, counterweight, and specifications.
- Containing high-quality diagrams and detailed instructions, this manual is a valuable tool for servicing and repairing your Clark forklift.
- It is an instant digital download, eliminating shipping costs and waiting time for delivery. Upon payment completion, you will receive the manual promptly through our secure payment processor.
- Compatible with all versions of Windows, Mac, as well as various devices such as iPhone, iPod, and Android, the manual is available in English and requires Adobe Reader for viewing.
Investing in this manual will not only save you money on service repair and maintenance costs but also enhance your understanding of your Clark forklift. All pages are printable for easy reference during maintenance and repairs.